The hypothalamus: physiology and clinical use of releasing factors

The importance of preserving the superior hypophyseal artery infundibular branch in craniopharyngioma surgery

PURPOSE

Postoperative pituitary dysfunction, a critical problem in the treatment of craniopharyngiomas, can occur even when the pituitary stalk is preserved. We hypothesized that compromise of the primary superior hypophyseal artery (pSHA) might be related to this occurrence.

METHODS

We performed a retrospective review of 131 patients with craniopharyngioma who underwent surgery from April 2009 to September 2021. The inclusion criteria were initial surgery, endoscopic transsphenoidal surgery, preoperative normal pituitary function or pituitary dysfunction in one axis, and morphological preservation of the pituitary stalk. The branches of the pSHA consist mainly of the chiasmatic branches (Cb), infundibular branches (Ib), and descending branches (Db). We analyzed the association between postoperative pituitary function and preservation of these branches.

RESULTS

Twenty patients met the criteria. Preoperative anterior pituitary function was normal in 18 patients, and there was isolated growth hormone deficiency in two patients. No patient had preoperative diabetes insipidus (DI). Anterior pituitary function was unchanged postoperatively in eight patients. Of these eight patients, bilateral preservation of pSHA Ib was confirmed in seven patients. Bilateral preservation of pSHA Ib was the only factor associated with preserved anterior pituitary function (p < 0.01). Fifteen patients were free of permanent DI, and the preservation of any given pSHA branch produced no significant difference in the postoperative occurrence of permanent DI.

CONCLUSIONS

Our study shows that bilateral preservation of pSHA Ib provides favorable postoperative anterior pituitary function in craniopharyngioma surgery; however, such preservation may have little effect on the postoperative occurrence of DI.

Ovulation induction with luteinizing hormone--releasing hormone in amenorrheic, infertile women

Thirteen women with infertility thought due to anovulation were treated with LRH. Etiologic diagnoses of amenorrhea included hypothalamic or "idiopathic" and PCOD. All patients had normal gonadotropins and otherwise normal endocrinologic and infertility evaluations; none had ovulated with clomiphene. Patients were studied for six 35 day cycles, single blind, and received LRH or placebo by subcutaneous injections for 28 days/cycle (LRH dosage 1.0 mg 2 or 3 times each day). Frequent assessments of physical status, cervical mucus, vaginal cytology, and serum LH, FSH, estrogen, and progesterone were performed. Ovulation was documented by basal temperature, serum progesterone and, on occasion, endometrial biopsy. Follow-up was continued for 6 months after therapy. Of the 13 patients treated, eight have ovulated and five have conceived. There were no complications of therapy.

Effects of a luteinizing hormone-releasing hormone analog on mating and fertility in rats

A rhythmic antifertility effect of a luteinizing hormone-releasing hormone (LH-RH) analog, [D-Ala6-des-Gly-NH210]-LH-RH-ethylamide (AY-25,205), administered intramuscularly every 3rd day staring in the afternoon of diestrus, was demonstrated in 4-day cyclic rats. The antifertility effect was achieved for a period of approximately four cycles when the females were allowed constant cohabitation with fertile males except for 24 hours following treatment. Unrestricted cohabitation resulted in some matings and pregnancies in the group treated every 3rd day and also in some of the groups treated every 4th day with restricted cohabitation. The antifertility effect of AY-25,205, with unrestricted cohabitation, disappeared when the second treatment was given 4 days after the first. It is presumed that the antifertility effect of AY-25,205 was achieved through its capacity to induce ovulation at a physiologically "wrong time" (i.e., 1 day before the expected day of proestrus) and through its effect on mating behavior. The present experimental models suggest that AY-25,205 or similar analogs could be potentially useful for a more reliable rhythm method of birth control in humans, by timing ovulation and narrowing the fertile period of the cycle.

[Structural changes of the basement tubule membrane in the so-called Sertoli cell syndrome (author's transl)]

In the so-called Sertoli cell syndrome nearly always club shaped invaginations of the basement tubule membrane with intact cellule membrane can be seen. These protuberatons ultrastructurally prove to be multiplicated piles of the lamina densa of the basement membrane. The cells in the Sertoli cell syndrome show a quantitatively and qualitatively reduced pattern of enzymes in contrast with the active Sertoli cells.

ACTH content of pituitary glands of arteriosclerotic breeder vs. non-arteriosclerotic virgin rats

Acid extracts were made of the pituitary glands of non-arteriosclerotic male and female virgin rats and arteriosclerotic, male and female breeder rats. The ACTH content of these pituitary glands was determined by measuring the amount of corticosterone produced by the adrenal glands of healthy but hypophysectomized rats when challenged by the various ACTH acid extracts. The pituitary glands of the arteriosclerotic animals were significantly heavier than non-arteriosclerotic rats and contained decreased amounts of ACTH commensurate with the severity of the pituitary donor's arteriosclerosis. Similarly, arteriosclerotic donors had heavier adrenal glands but contained considerably less corticosterone than non-arteriosclerotic virgin rats. Male breeder rats developed microscopic aortic lesions involving intimal mesenchymal cell and ground substance alterations whereas the female breeder lesions progressed from intimal ground substance and connective tissue changes to medial elastolytic degeneration and eventual medial cartilaginous and osseous metaplasia. Histopathologic examination of the pituitary and adrenal glands demonstrated hyperplasia of basophil and other cytologic elements of the pituitary gland including colloid-filled cysts and lipid depletion of the zona glomerulosa as well as hemorrhage and thrombosis of the adrenal cortex of the arteriosclerotic breeder rats. The hypothesis is made that repeated breeding leads to abnormal hypothalamic regulation of pituitary gland synthesis and release of ACTH, which, in turn, contributes to abnormal adrenal glandular function conditioning the aortic wall toward abnormal changes in mesenchymal cell activity and metabolism of connective tissue ground substance.

Induction of timed ovulation with synthetic luteinizing hormone-releasing hormone in women undergoing insemination therapy. I. Effect of a single parenteral administration at midcycle

Synthetic LH-RH was administered by various routes to 19 patients during 37 treatment cycles in an attempt to trigger ovulation in association with insemination therapy. Thirty-five cycles were ovulatory; four pregnancies occurred, but two of them ended in spontaneous abortion. In 20 cycles, the hyperthermia response occurred one to three days after LH-RH administration, suggesting that ovulation occurred as a direct consequence of administered LH-RH. Low levels and delayed peak secretion of progesterone were found in two patients who had serial progesterone determinations during the luteal phase after LH-RH administration. Ovulation timing with LH-RH appears feasible, but efforts to ensure the availability of a mature follicle are required.