Changes in hormones, metabolites, and milk after treatment with sometribove (recombinant methionyl bST) in Deutsches Fleckvieh and German black and white cows

Twelve second-lactation Deutsches Fleckvieh cows, (FV, a dual-purpose breed) and 12 German Black and White (BW, a dairy breed) were used to evaluate similarities and differences in the response to a prolonged-release formulation of sometribove (N-methionyl bovine somatotropin, bST). Cows were milked twice daily and fed a basic diet (70% corn silage, 30% alfalfa hay) ad libitum plus 1 kg of concentrate. Additionally, concentrates and supplements were offered at the rate of 1 kg for each 22 kg of milk produced above 12 kg/d. Six cows of each breed were treated s.c. with 500 mg of sometribove at 14-d intervals from wk 9 to 29 postpartum (pp). Blood was collected by jugular vein puncture once weekly from wk 7 to 33 pp and daily for 14 d after the first and last (11th) injection of bST. Somatotropin (ST), insulin-like growth factor I (IGF-I), insulin, thyroid hormones, nonesterified fatty acids (NEFA), liver enzymes, and blood metabolites were evaluated. During bST treatment, plasma ST increased significantly on d 7 in both breeds and then decreased on d 14 after injection. Plasma IGF-I was positively correlated with ST. Plasma NEFA were high on d 7 and decreased on d 14. In response to bST, the average milk yield increased for FV and BW cows by 5.1 kg/d (29.7%) and 5.0 kg/d (28%), respectively, and 4% fat-corrected milk (FCM) increased by 5.0 kg/d (28%) and 5.3 kg/d (19.9%), respectively. Milk content of fat, protein, lactose, number of somatic cells, and body weight were similar across treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid synthesis by co-cultures of mammary, liver, and adipose tissue explants from sometribove (recombinant methionyl bovine somatotropin)-treated dairy cows

Bovine somatotropin was given to six lactating (230 day) cows (40 mg/day X 5-days) and excipient was given to six control cows. Mammary, liver, and adipose explants from somatotrophin and control cows were co-cultured at 37 degrees C for 24 h with 0.5 microCi [14C]acetate/ml media with or without 0.5 micrograms/ml somatotrophin. Tissue lipids were extracted with chloroform/methanol and separated by thin layer chromatography. In vivo somatotrophin increased milk production 2.4 kg/day compared to a 0.9 kg/day decrease by controls. Mammary tissue from somatotrophin cows incorporated more [14C]acetate into total lipids (4417 vs. 3016 dpm/mg tissue) than controls. Adding somatotrophin to explant cultures from somatotrophin cows further increased incorporation into total lipids (4839 vs. 3994 dpm/mg tissue). In contrast, adipose tissue from somatotrophin cows incorporated less [14C]acetate into total lipids than controls (1524 vs. 2581 dpm/mg tissue). Serum IGF-I concentration correlated well (r = 0.69) with milk output differences between Days 1 and 5 of treatment. Media IGF-I concentration correlated well (r = 0.61) with the difference in total lipid synthesis between the in vitro control and somatotrophin groups. Results support the concept that somatotrophin increases milk production by partitioning nutrients away from adipose toward mammary tissue.

Responses by lactating cows in commercial dairy herds to recombinant bovine somatotropin

Cows (890) in 15 US herds were assigned randomly in equal numbers to control or bST injections (500 mg in a prolonged-release form every 14 d for 12 wk) within three stages of lactation (57 to 100, 101 to 140, and 141 to 189 d postpartum) and two parity groups (primiparous and multiparous). Yield and milk composition were monitored 1 d/wk for 16 wk including 2 wk pretreatment and 2 wk posttreatment. Increases in milk and FCM due to bST injections were less at 57 to 100 d than at 101 to 189 d postpartum (milk 3.6 vs. 5.5; FCM 3.9 vs. 6.1 kg/d per cow), and increases in milk and FCM were more for multiparous than for primiparous cows (milk 5.5 vs. 4.2; FCM 6.0 vs. 4.7 kg/d cow). Temporarily, concentration of milk fat increased and protein decreased; later, concentrations for control and injected cows were similar. Postinjection milk fat concentration decreased, but milk protein concentration increased temporarily. The net increase in milk (and FCM) varied significantly among herds from 2.9 to 7.6 kg/d per cow (mean, 4.9 kg). Responses in FCM were similar over a wide range of pretreatment yields. A great variety of feed ingredients were fed as total mixed rations, and nutrient concentrations varied greatly. The SCC were similar before, during, and after treatment, but increase in FCM of injected cows exhibited a negative correlation with pretreatment SCC. Changes in body condition score of sometribove-injected cows varied among herds (.25 to -.45) and averaged -.02 compared with .07 for controls. There was no pattern in incidence of mastitis during sometribove injections.

Growth hormone inhibits activation of phosphatidylinositol phospholipase C in adipose plasma membranes: evidence for a growth hormone-induced change in G protein function

Pituitary growth hormone (GH) functions physiologically to oppose the actions of insulin on carbohydrate and lipid metabolism by interfering with metabolic events that occur after insulin binds to its receptor. Which postreceptor effects are involved is presently unknown. Recently, we found that insulin rapidly stimulates a phosphatidylinositol phospholipase C (PI-PLC) in adipose tissue of obese (ob/ob) mice and that this effect of insulin is blocked by treatment of the animals with S-carboxymethylated human GH (RCM-hGH), a derivative having mainly anti-insulin activity. The activation of this PI-PLC by insulin is also inhibited by pertussis toxin. Thus, this study was performed to examine whether the inhibitory effect of GH on the activation of this PI-PLC is exerted at the level of signal transmission by guanine nucleotide binding proteins (G proteins). We found that the nonhydrolyzable GTP analogue, guanosine 5'-[gamma-thio]triphosphate, stimulated basal PI-PLC activity in plasma membranes of adipose tissue of saline-treated ob/ob mice, but it did not stimulate the enzyme in adipose membranes from RCM-hGH-treated mice. Also, RCM-hGH treatment markedly inhibited pertussis toxin-catalyzed ADP ribosylation of G protein alpha subunits in the membranes, suggesting some modification of the G proteins by GH. Immunoblot analysis of adipose membranes from saline- and RCM-hGH-treated mice using antiserum AS/7 (anti-Gi1 alpha and anti-Gi2 alpha) or antiserum EC/2 (anti-Gi3 alpha) showed no difference in the amount of Gi alpha-like protein between the groups. These findings suggest that GH interferes with the ability of a putative Gi-like protein to mediate the activation of PI-PLC in adipose membranes without altering the expression of the G protein.

Growth hormone improves muscle protein metabolism and whole body nitrogen economy in man during a hyponitrogenous diet

Healthy male volunteers (n = 12) were given a normocaloric hyponitrogenous diet for a conditioning period of 7 days. Thereafter they were blindly randomized to receive daily injections of methionyl recombinant human growth hormone (met-hGH) 0.06 IU/kg or saline during a second week of hyponitrogenous nutrition. The met-hGH group showed a lower urinary urea excretion and a lower serum concentration of urea as compared with the control group. In skeletal muscle, the polyribosome concentration, indicative of muscle protein synthesis, as well as the concentrations of glutamine, alanine, aspartate, serine, and threonine, decreased in the control group, whereas no such changes were seen in the met-hGH-treated group. Since provision of met-hGH prevented protein catabolism in muscle and improved whole body nitrogen economy, investigations of the possible beneficial effects of met-hGH to prevent skeletal muscle vast after surgical trauma are advocated.

Growth hormone (GH) autofeedback on GH response to GH-releasing hormone. Role of free fatty acids and somatostatin

Methionyl-GH (met-GH) infusions inhibit the GH response to GH-releasing hormone (GHRH). Met-GH infusions induce lipolysis with a rise of plasma FFA that are known to suppress GH release, but the met-GH inhibition of the GH response to GHRH occurs also when lipolysis is pharmacologically blocked by acipimox. In addition, the inhibition of GH release might be due to an enhanced release of hypothalamic somatostatin. The aim of this study was to evaluate the effect of a met-GH infusion on the GH response to GHRH when lipolysis and hypothalamic somatostatin release are pharmacologically blocked. Twelve normal subjects, randomly allocated to two groups (A and B), received GHRH (50 micrograms, iv) at 1300 h after a 4-h saline infusion or met-GH infusion (80 ng/kg.min). To block lipolysis and hypothalamic somatostatin release, subjects in group B received acipimox, an antilipolytic agent (500 mg), and pyridostigmine, an acetylcholinesterase inhibitor (60 mg), during the 6 h before iv GHRH. GHRH induced a clear GH release during saline infusion in both groups, significantly higher in group B (43.6 +/- 4.8 micrograms/L) than in group A (20.1 +/- 6.1 micrograms/L; P less than 0.02 vs. A), and only a slight increase during met-GH infusions (10.4 +/- 4.1 micrograms/L in group A; 16.7 +/- 4.2 micrograms/L in group B; P = NS). These data indicate that the GH response to GHRH is inhibited by met-GH infusions when peripheral lipolysis and hypothalamic somatostatin release are pharmacologically blocked, suggesting the possibility of autoinhibition of GH at the pituitary level.

Comparison of the immunogenicity of recombinant and pituitary human growth hormone in rhesus monkeys

The relative concentrations of antibodies produced in monkeys against three forms of human growth hormone (hGH) were determined using an antigen-specific avidin/biotin ELISA assay. Monkeys were treated in two separate 90-day studies with recombinant methionyl-hGH (met-hGH) and pituitary-derived hGH (pit-hGH) (Study 1) and recombinant natural sequence hGH (Study 2). The lowest dose was equal to the expected therapeutic dose of 0.1 IU/kg. Sixty-nine percent of monkeys treated with pit-hGH and 81% of those treated with met-hGH developed detectable anti-hGH responses. The magnitudes of the responses exhibited wide animal to animal variability, were not markedly related to dose or sex, and were lower than levels obtained in monkeys immunized with hGH in Freund's adjuvant. In contrast, the incidence of antibody responses in monkeys treated with natural sequence hGH was lower (23% in one experiment and 5% in a replicate experiment) and took longer to develop. Antibody concentrations were lower, on average, than in those animals treated with met- or pit-hGH. These results are in accord with those observed clinically, thus supporting the use of the monkey model to predict the relative immunogenicity of some proteins in humans.

Growth hormone and prolactin secretion in hypophysial stalk-transected pigs as affected by growth hormone and prolactin-releasing and inhibiting factors

Control of growth hormone (GH) and prolactin (PRL) release was investigated in hypophysial stalk-transected (HST) and stalk-intact pigs by determining the effects of analogs of GH-releasing factors (GHRF), somatostatin (SRIF), arginine, thyrotropin-releasing hormone, alpha-methyl-rho-tyrosine, and haloperidol. HST and control gilts were challenged with intravenous injections of human pancreatic GHRF(1-40)OH, thyrotropin-releasing hormone, and analogs of rat hypothalamic GHRF. HST animals remained acutely responsive to GHRF by releasing 2-fold greater quantities of GH than seen in controls. This occurred in spite of a 38% reduction in pituitary gland weight and a 32 and 55% decrease in GH concentration and total content. During SRIF infusion, GH remained at similar basal concentrations in HST and control gilts, but increased immediately after stopping SRIF infusion only in the controls. Releasable pituitary GH appears to accumulate during SRIF infusion. GHRF given during SRIF infusion caused a 2-fold greater release of GH than seen in animals receiving only GHRF. Arginine increased (P less than 0.05) GH release in controls, but not in HST gilts, which suggests that it acts through the central nervous system. Basal PRL concentrations were greater (P less than 0.05) in HST gilts than in control gilts. TRH acutely elevated circulating PRL (P less than 0.001) in HST gilts, suggesting that it acts directly on the pituitary gland. Haloperidol, a dopamine receptor antagonist, increased circulating PRL in controls but not in HST animals. alpha-Methyl-rho-tyrosine did not consistently increase circulating PRL, however, suggesting that it did not sufficiently alter turnover rate of the tyrosine hydroxylase pool. The results indicate that the isolated pituitary after HST remains acutely responsive to hypothalamic releasing and inhibiting factors for both GH and PRL release in the pig.

Immune function in growth hormone-deficient children treated with biosynthetic growth hormone

Conflicting data regarding the immune function in growth hormone (GH) -deficient children or changes in immune parameters during substitutive GH therapy have been reported. We have studied the immune function in 13 patients with GH deficiency before and during treatment with biosynthetic GH (12 IU/m2 body surface/week) after 6 and 12 months of therapy. We found that the absolute number of total T lymphocytes and T-cell subsets (using monoclonal Ab as markers), Natural Killer cell activity (target K562) and response of lymphocytes to polyclonal mitogens (PHA, ConA, PWM) were all in the normal range and remained so after 6 and 12 months of therapy. The absolute number of B lymphocytes was in the normal range before treatment and after 6 months of therapy but dropped significantly after 12 months of treatment. Serum immunoglobulins (IgG, IgA, IgM) did not show a parallel drop and remained normal throughout the whole study. Our GH-deficient patients did not show any undue susceptibility to infections and our data thus seem to confirm that the immune function is basically intact in these children and that it is not suppressed by GH treatment. Although a drop in B lymphocytes was observed, the normal level of immunoglobulins and the normal functional response to PWM seem to demonstrate the maintenance of a normal humoral immune response.

Effect of long-term bovine somatotropin (sometribove) treatment on nitrogen (protein) distribution in Jersey milk

Twenty-six Jersey cows were assigned randomly to one of two treatments. Twelve cows received biweekly subcutaneous injection of 500 mg of sometribove, USAN (recombinant methionyl bovine somatotropin), beginning 60 +/- 3 d postpartum and continuing throughout one lactation. Fourteen control animals received injections of placebo carrier. Milk samples were taken biweekly on weeks alternate to injection when differences in milk components were expected to be greatest compared with controls. The milk samples were analyzed for total nitrogen, noncasein nitrogen, and non-protein nitrogen. The average SCC for control and treatment groups was 44,000 +/- 47,000 and 56,000 +/- 65,000. Milk from sometribove-treated cows was significantly lower in total protein (3.92, 4.12%), true protein (3.74, 3.95%), and casein (3.11, 3.34%) than that from control cows on d 8 of the 14 d injection cycle. Casein as a percentage of true protein was lower (83.38, 84.52%), and non-protein nitrogen as a percentage of total nitrogen was higher (4.61, 4.26%) in milk from treated cows. The theoretical yield of Cheddar cheese was ca. .07% less for milk from treated cows than from control cows due to ca. 1% less casein as a percentage of true protein in the former. The differences in nitrogen distribution represent the response during the middle of the injection cycle when milk output was the highest and milk protein the lowest rather than the average response for the injection cycle. The results of the study indicate minimal impact on the cheese manufacturer because in practice milk is commingled from many dairies.(ABSTRACT TRUNCATED AT 250 WORDS)

Exogenous human growth hormone reduces body fat in obese women

The effects of biosynthetic methionyl human growth hormone (met-hGH) on body composition and endogenous secretion of insulin-like growth factor I (IGF-I) were studied in obese women ranging between 138 and 226% of ideal body weight. Following double-blind procedures, 12 subjects were assigned at random to either treatment with met-hGH (n = 6, 0.08 mg/kg desirable body weight) or placebo (n = 6, bacteriostatic water diluent). Treatments were delivered intramuscularly three times per week for a period of 27-28 days. Subjects were instructed to follow a weight-maintaining diet and their pre- and posttreatment kilocaloric intake was monitored for verification. The baseline peak serum GH response to L-dopa/arginine stimulation for the study population as a whole, was in the hyposecretory range (9.6 +/- 1.9 ng/ml), accompanied by a low level of circulating IGF-I (0.56 +/- 0.09 U/ml). Hydrodensitometry revealed that the met-hGH-treated subjects had a significant reduction in body fat, while an observed mean increase in fat-free mass (FFM) approached significance. The percent change in body fat was unrelated to pretreatment levels of body fat, total body weight, or initial endogenous GH status. Changes in circulating IGF-I were similar to those for FFM, with increases approaching significance. There were no significant changes in body composition or IGF-I in the placebo-treated subjects. No significant differences were observed in the self-reported dietary intake of kilocalories during the experimental period between the two groups. We conclude that exogenous GH reduces body fat in obese women in the apparent absence of significant kilocaloric restriction. The effect appears to be unrelated to endogenous GH secretion or body composition.

Effects of recombinant methionyl bovine somatotropin (sometribove) in high producing cows milked three times daily

Effects of daily sometribove administration on milk yield and composition, body condition score, BW, and SCC were evaluated in Holstein cows milked three times daily. Lactating cows (n =104) were assigned randomly to control or sometribove-treated (25 mg/d) groups. The experimental period was 16 wk, consisting of 2-wk pretreatment, 12-wk treatment, and 2-wk posttreatment periods. All cows were injected once daily starting at 53 to 180 d postpartum, housed in free stalls, and fed one of five total mixed rations according to milk production. Body weights were measured weekly, and body condition was scored biweekly. Milk yield was recorded daily, and weekly milk samples were analyzed for fat, protein, lactose, total solids, and SCC. Milk yield and milk protein were increased 18.8% (38.6 vs. 32.5 kg/d) and 3.3% (3.1 vs. 3.0%), respectively, whereas percentage of milk fat, lactose, SNF, SCC, and BW were unaffected by treatment. Overall average body condition scores were lower for the sometribove-treated group versus control (2.2 vs. 2.4). No apparent differences in the number of cows treated for mastitis, foot rot, displaced abomasum, or lameness were observed between treatment groups. Sometribove treatment significantly enhanced milk yield (6.1 kg/d) with no apparent negative effects on health in high producing cows milked three times per day.

Supplemental growth hormone increases the tumor cytotoxic activity of natural killer cells in healthy adults with normal growth hormone secretion

Using double-blind, placebo-controlled procedures, the effects of methionyl-human growth hormone (met-hGH) on the tumor cytotoxic activity of natural killer (NK) cells were studied in seven healthy adults using a repeated measures experiment. Subjects were assigned at random to either a placebo (bacteriostatic water) treatment condition or a met-hGH (16.0 mg/wk of Protropin) treatment condition, then crossed-over to the alternative treatment. Treatments were delivered on alternate days (3 d/wk) for 6 weeks. Without bias from the met-hGH treatment, there was no evidence for GH hyposecretion as measured by the peak circulating GH response to exercise stimulation (14.1 +/- 3.1 ng/mL) or insulin-like growth factor (IGF-I) levels (0.82 +/- 0.09 U/mL). When compared with placebo, met-hGH induced a significant overall increase in the percent specific lysis (%SL) of K562 tumor target cells (placebo 22.2 +/- 1.7 v met-hGH 28.5 +/- 2.1 %SL; P = .008). NK activity was increased within the first week of treatment and this level was maintained throughout the remaining period of supplementation. There was a trend (P = .057) for the met-hGH-induced percent change in NK activity (NK%) to be inversely related to placebo IGF-I levels (r = -.761), while there were significant positive correlations between NK% and the met-hGH-induced percent changes in IGF-I (r = .727; P = .035), the fat-free mass (FFM)/fat mass (FM) ratio derived by hydrodensitometry (r = .792; P = .012), and the endogenous GH response to exercise (r = .469; P = .034).(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary human growth hormone measurement using a highly sensitive sandwich enzyme immunoassay: diagnostic and therapeutic uses in patients with growth hormone deficiency

Several reports indicate that urinary hGH excretion is significantly lower in patients with either partial (PGHD) or complete GH deficiency (CGHD) than in normal but short children (NSC) or normal children (NC). However, there is an overlap between the NSC and NC groups and the PGHD group. Using a highly sensitive sandwich enzyme immunoassay, we investigated whether the measurement of urinary hGH can clearly separate the PGHD and CGHD groups from the NSC and NC groups. In addition, we measured the urinary excretion of synthetic methionyl-hGH (met-hGH) in PGHD and CGHD after sc injections of 2 and 4 IU and im injections of 4 IU in an attempt to determine the optimal replacement dose. Total 24-h urinary hGH excretion in each patient examined for 2 consecutive days varied from 1 day to the next. There were no differences in urinary hGH excretions between the NSC group and the NC group. The lower values for daily urinary hGH excretion in the NSC group overlapped some of the higher values in the PGHD group. However, when the mean urinary hGH level of both days was used, the 24-h urinary hGH excretion clearly separated the PGHD (5.5 +/- 2.3 ng/day; range, 1.3-9.2; n = 21) and CGHD (1.9 +/- 0.9 ng/day; range, 0.6-3.6; n = 14) groups from the NSC (12.8 +/- 3.1 ng/day; range, 9.3-17.5; n = 10) and NC (14.6 +/- 3.1 ng/day; range, 10.6-19.0; n = 6) groups without any overlap. A mean urinary hGH value less than 9.0 ng/day during a 2-day collection strongly suggested GH deficiency. Ten of 16 patients with PGHD and CGHD who received 2 IU met-hGH, sc, had urinary hGH levels within the range of the mean +/- SD in NSC. These patients received daily sc 0.097 +/- 0.024 IU/kg hGH injections. These results suggest that the measurement of 24-h urinary hGH excretion is noninvasive, accurate, and useful for the screening of GH deficiency. The mean value on 2 days of 24-h urinary hGH excretion for the screening of GH deficiency is estimated to be less than 9.0 ng/day. The optimal dose of GH as therapy for GH deficiency is demonstrated as daily sc injection of 0.1 IU/kg hGH, 0.7 IU/kg/week. To convert international units of met-hGH to milligrams, divide by 2.4.

[Clinical and biochemical evaluation of the administration of growth hormone]

Ten children with isolated growth hormone deficiency were treated for 1 year with 0.5 UI/kg week with Somatrem (recombinant human growth hormone), given as intramuscular injections three times weekly. Before treatment the children had a chronological age of 7-12.4 years (mean 10.4 years), with a bone age at least 25% below the chronological age. There was no radiological evidence of an intra or suprasellar mass in any child, and no response to provocative growth hormone tests (with exercise or arginine-insulin injection). Informed written consent for treatment was obtained from the parents of each child. Clinical signs were registered every month; triiodothyronine, thyroxine, thyrotropine, glucose, urea, creatinine, blood cells count, and hemoglobine, glycosylated hemoglobine, glutamic-piruvic and glutamic-oxalacetic transaminases, alkaline phosphatase, anti-human growth hormone and, E. coli antibodies, insulin like growth factor 1, and bone age were assessed every 3 months. The mean height velocity was 0.27 +/- 0.1 cm/month before treatment, and increased throughout treatment to a value of 0.62 +/- 0.16 cm/month after 12 months. Within the first year eight of the 10 children had a height increase of 8.4 +/- 0.98 cm. The other two children showed no significant difference; one of them with a very low socioeconomic status, and the other developed typhoid fever. All of the children showed an advance in bone age, but none reached a bone age appropriate for their chronological age; without modifications in the laboratory parameters. Insulin like growth factor 1 increased in 9 children. Pain at the injection site was the only side effect reported.

The growth hormone clamp technique: inhibition of growth hormone release by growth hormone occurs independently of free fatty acids

It has been suggested that growth hormone (GH) can inhibit its own release: in fact it has repeatedly been shown that an acute methionyl-GH (met-GH) infusion blocks the GH response to GH-releasing hormone (GHRH). However, met-GH infusions are accompanied by a significant increase of free fatty acids (FFA), which can block GH release. The aim of this study was to evaluate whether the inhibition of GH response to GHRH also occurs when lipolysis is pharmacologically blocked. Therefore, six normal subjects received GHRH, 50 micrograms intravenously (IV), after a 4-hour saline infusion and a 4-hour met-GH infusion (80 ng/kg/min, yielding a constant GH level of 33.6 +/- 4.63 micrograms/L), and GH release was evaluated during the following 2 hours. To prevent lipolysis, all subjects received on both occasions acipimox, an antilipolytic agent, 500 mg during the 6 hours before IV GHRH. GHRH induced a clear GH release during saline infusion (46.6 +/- 2.70 micrograms/L) and a scanty GH release during met-GH infusion (9.3 +/- 1.52 micrograms/L; P less than .01). Plasma levels of FFA, somatostatin, insulin-like growth factor I (IGF-I), and glucagon and serum insulin levels were unaffected, while blood glucose levels slightly decreased during saline infusion, but not during GH infusion. These data confirm that met-GH inhibits GHRH-induced GH release, and demonstrate that this inhibition is not mediated by FFA levels.

Identification of placental human growth hormone as the growth hormone-V gene expression product

A GH variant of placental origin, placental GH, has recently been shown to replace pituitary GH in maternal serum during pregnancy. Besides, the GH variant (GH-V) gene has been demonstrated to be expressed in the placenta. The similarities between their known properties strongly suggest that the placental GH and the GH-V protein are the same molecular species. Here we provide final evidence that this is indeed the case by sequence analysis of both the 22K and 25K forms. Furthermore, the 25K form is shown to be glycosylated, while the 22K form is not. Both size variants of placental GH are, thus, likely to reflect the partial glycosylation of a unique peptidic chain.

Growth hormone treatment in the United States: demographic and diagnostic features of 2331 children

Demographic, diagnostic, and baseline clinical data were collected for a large cohort (N = 2331) of children who started treatment with biosynthetic human growth hormone (GH) between October 1985 and October 1987. Eighty-one percent met classic criteria for GH deficiency and were classified as having idiopathic GH deficiency (59%), organic GH deficiency (18%), or septo-optic dysplasia (4%). The remaining 19.8% had short stature of varied causes. Height standard deviation score at diagnosis, maximum GH response to stimulation, and heights of parents were examined according to gender, race, age at diagnosis, and previous treatment history. The predominance of boys in all subgroups except septooptic dysplasia, and the observation that girls with idiopathic GH deficiency were comparatively shorter than boys at diagnosis, suggest ascertainment bias. Black children with idiopathic GH deficiency were shorter than white children at diagnosis, and their low overall representation (6.0%) compared with their percentage in the at-risk population (12.9%) also suggest ascertainment bias among races. These data provide a profile of GH deficiency as it is currently defined and expose possible inherent biases in the diagnostic process. Now that GH supply is no longer limited, criteria for its use should be formulated to avoid apparent underascertainment or late diagnosis of GH deficiency in girls and black children.

Two-year results of treatment with methionyl human growth hormone in children with Turner syndrome. Dutch Growth Hormone Working Group

Methionyl growth hormone (somatrem) in a daily dosage of 4 IU/m2 body surface area was administered to 16 girls with Turner syndrome. Low dose ethinyl estradiol (0.1 microgram/kg body weight) was added in girls aged 13 years or more. Mean (SD) height velocity increased from 3.4 (0.9) to 7.2 (1.7) and 5.3 (1.3) cm/year in the first and second year, respectively. Bone age advanced 1.8 years over 2 years and predicted adult height was increased. Apart from the occurrence of anti-GH antibodies there were no side effects. In conclusion, somatrem is an efficacious and safe therapy for short stature in Turner syndrome over a period of 2 years. Longer follow-up is needed before conclusions about its effect on final height can be drawn.

[Results of the treatment of growth hormone deficiency with methionine-somatotropin or recombinant somatotropin]

Sixteen children with hGH deficiency were treated for a year with methionyl-somatotropin (Somatonorm) or recombinant-somatotropin (Genotropin). The hormone was administrated subcutaneously 3 time/week, 0.45-0.6 IU/kg/week. After a year of treatment, the mean growth rate in those who received Somatonorm increased from 3.96 +/- 0.8 cm/yr to 9.08 +/- 2.7 cm/yr, and in those who received Genotropin from 3.6 +/- 0.6 cm/yr to 8.58 +/- 1.1 cm/yr with no significant difference. No adverse effects were observed, but four children that received Somatonorm developed antihGH antibodies with a very low binding capacity, of less than 0.1 mg/L. All the children that received Genotropin were negative for antihGH antibodies.

Growth hormone by daily injection in patients previously treated for growth hormone deficiency

When recombinant-DNA-derived methionyl growth hormone (met-GH) became available for patients resuming treatment, we were able to compare dose intervals in 47 prepubertal children with growth hormone deficiency. Patients were randomly assigned to one or three doses weekly or to daily injections for a total dosage of 0.3 mg/kg weekly. If the patient's annual growth failed to increase more than 2 cm above baseline, the dose interval was changed from weekly to three times a week or from three times a week to daily. In the second year of the study, all patients received daily injections. Despite a mean duration of previous treatment with growth hormone of more than 3 years, daily injections in 16 patients throughout the first year of the study resulted in a mean growth velocity (9.6 +/- 2.4 cm) comparable to that in newly treated patients given met-GH three times weekly in other trials. Administration by daily injection was more effective than injection three times per week (P less than .05) in 13 patients (7.9 +/- 2.1 cm) or once a week in four patients (7.7 +/- 1.2 cm). Second year growth velocities in 21 patients who had received once-a-week or three-times-a-week injections the first year of the study, increased significantly with a change to daily injection (7.7 +/- 2.2 vs 8.8 +/- 1.9 cm) (P less than .05).

Analysis of protein digests by capillary high-performance liquid chromatography and on-line fast atom bombardment mass spectrometry

An HPLC system incorporating a packed capillary C18 column has been utilized for high sensitivity peptide mapping and preparative collection for protein sequencing. This system combined with a Frit-FAB mass spectrometer interface also provides the ability to obtain molecular ions for peptides of enzymatically digested proteins in the time it takes to obtain an HPLC chromatogram. The low flow rates permit introduction of the entire column effluent into the mass spectrometer. Detection limits of 0.5-5 pmol are routine. Proteolytic digests of recombinant human methionyl growth hormone and protein carboxyl methyltransferase have been used to demonstrate the HPLC and mass spectrometer performance.