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Chen Y, Liu Y, Wang Y, Zhang Y, Xie W, Zhang H, Weng Q, Xu M. Expression of cholesterol synthesis and steroidogenic markers in females of the Chinese brown frog ( Rana dybowskii) during prespawning and prehibernation. Am J Physiol Regul Integr Comp Physiol 2023; 325:R750-R758. [PMID: 37867473 DOI: 10.1152/ajpregu.00296.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 10/24/2023]
Abstract
The oviduct of the Chinese brown frog (Rana dybowskii) expands in prehibernation rather than in prespawning, which is one of the physiological phenomena that occur in the preparation for hibernation. Steroid hormones are known to regulate oviductal development. Cholesterol synthesis and steroidogenesis may play an important role in the expansion of the oviduct before hibernation. In this study, we investigated the expression patterns of the markers that are involved in the de novo steroid synthesis pathway in the oviduct of R. dybowskii during prespawning and prehibernation. According to histological analysis, the oviduct of R. dybowskii contains epithelial cells, glandular cells, and tubule lumens. During prehibernation, oviductal pipe diameter and weight were significantly larger than during prespawning. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGCR), low-density lipoprotein receptor (LDLR), steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) were detected in epithelial cells in prehibernation and glandular cells during prespawning. HMGCR, LDLR, StAR, and P450scc protein expression levels were higher in prehibernation than during prespawning, but the SF-1 protein expression level did not significantly differ. HMGCR, LDLR, StAR, P450scc (CYP11A1), and SF-1 (NR5A1) mRNA expression levels were significantly higher in prehibernation compared with prespawning. The transcriptome results showed that the steroid synthesis pathway was highly expressed during prehibernation. Existing results indicate that the oviduct is able to synthesize steroid hormones using cholesterol, and that steroid hormones may affect the oviductal functions of R. dybowskii.
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Affiliation(s)
- Yuan Chen
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Yuning Liu
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Yankun Wang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Yue Zhang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
| | - Wenqian Xie
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Haolin Zhang
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Qiang Weng
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
| | - Meiyu Xu
- Laboratory of Animal Physiology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China
- Beijing Key Laboratory of Food Processing and Safety in Forestry, Beijing Forestry University, Beijing, People's Republic of China
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Méndez-Tepepa M, Morales-Cruz C, García-Nieto E, Anaya-Hernández A. A review of the reproductive system in anuran amphibians. ZOOLOGICAL LETTERS 2023; 9:3. [PMID: 36782341 PMCID: PMC9926845 DOI: 10.1186/s40851-023-00201-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Reproductive biology is an important topic that is well explored in many vertebrates, but information about frogs' reproductive mechanisms could be improved. Therefore, this review aims to provide organized and specific information on frog reproduction. First, we developed schemes that illustrate the general information regarding reproductive biological mechanisms in frogs in a specific way. Then, we described the physiological, histological, and morphological mechanisms of each organ of the reproductive system of male and female frogs. Finally, this manuscript may contribute to a broader understanding of anuran reproductive biology. Since, understanding frogs' reproductive system permits one to make a comparison with reproduction with other anurans.
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Affiliation(s)
- Maribel Méndez-Tepepa
- Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Autopista San Martín-Tlaxcala Km 10.5, Ixtacuixtla, 90120, Tlaxcala, Mexico.
| | - Cuauhtémoc Morales-Cruz
- Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Autopista San Martín-Tlaxcala Km 10.5, Ixtacuixtla, 90120, Tlaxcala, Mexico
| | - Edelmira García-Nieto
- Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Autopista San Martín-Tlaxcala Km 10.5, Ixtacuixtla, 90120, Tlaxcala, Mexico
| | - Arely Anaya-Hernández
- Centro de Investigación en Genética y Ambiente, Universidad Autónoma de Tlaxcala, Autopista San Martín-Tlaxcala Km 10.5, Ixtacuixtla, 90120, Tlaxcala, Mexico
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Hadawale KN, Shewale SA, Shetye KC, Sagarkar S, Sakharkar AJ, Bhargava SY. Reproductive phase related variations in the expression of neuropeptide, cocaine- and amphetamine- regulated transcript (CART) in the brain and pituitary gland of adult male Microhyla ornata. Neurosci Lett 2022; 786:136783. [PMID: 35810962 DOI: 10.1016/j.neulet.2022.136783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/06/2022] [Accepted: 07/05/2022] [Indexed: 10/17/2022]
Abstract
Cocaine- and amphetamine-regulated transcript (CART) peptide is a multifaceted neuropeptide involved in several physiological functions including appetite and reproduction. While studies in mammals, aves and fishes suggest evolutionary conserved role of CART, the information in amphibian is scanty. We have investigated the reproductive phase related variations of CART in the brain of adult male Microhyla ornata. Seasonal changes in the expression of CART peptide were noticed in the brain and pituitary of M. ornata. Significant differences were observed in the nucleus infundibularis ventralis (NIV), epiphysis (E), anteroventral tegmental region (AV), raphe nucleus (Ra) of the brain and pars intermedia (PI), pars distalis (PD) of the pituitary. Compared to the pre-breeding and post-breeding seasons, increase in CART immunoreactivity was seen in E, NIV, AV, Ra of brain and PI, PD of pituitary gland of animals collected during breeding season. Similarly, highest mRNA levels of CART were also observed in the breeding season in the middle region of brain that includes hypothalamus and pituitary gland. Variation in the levels of CART peptide and mRNA in the brain of M. ornata suggests its conserved role in seasonal control of appetite and reproduction.
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Affiliation(s)
- Kavita N Hadawale
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411 007, India
| | - Swapnil A Shewale
- Department of Zoology, Bhavan's Hazarimal Somani College, Chowpatty, Mumbai 400 007, India
| | - Ketaki C Shetye
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411 007, India
| | - Sneha Sagarkar
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411 007, India
| | - Amul J Sakharkar
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411 007, India
| | - Shobha Y Bhargava
- Department of Zoology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411 007, India.
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Prado DMA, Gomes FR, Madelaire CB. Effects of corticosterone treatment and wound healing on reproductive traits of American bullfrogs. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:275-285. [PMID: 33411410 DOI: 10.1002/jez.2439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/20/2020] [Accepted: 12/18/2020] [Indexed: 11/05/2022]
Abstract
During reproductive season, calling anuran males display high testosterone (T) and episodically high corticosterone (CORT) plasma levels, which are positively associated with higher calling rates and immunocompetence. However, exposure to constant stress stimuli can result in chronically elevated CORT levels, possibly leading to inhibition of reproductive and immune activity. Reproduction and immune responses are energetically expensive, so when an animal is immunologically challenged, a tradeoff might be expressed, with CORT potentially mediating it. Our aim was to test how episodic and chronic CORT treatments, alongside wound healing, would affect reproduction in American bullfrog males (Lithobates catesbeianus). Forty animals were divided in four groups: Episodic CORT (daily transdermic application of CORT), placebo (daily transdermic application of sesame oil), chronic CORT (subcutaneous CORT silastic implants), and sham control (subcutaneous empty silastic implants). One week after treatments began, animals were punctured in the leg with a biopsy needle and the wound was photographed after 45 days to determine wound healing status (WS). Blood samples were collected throughout the experiment to measure CORT and T plasma levels. After animal euthanasia, testes were dissected, fixed, and analyzed histologically to determine spermatogenic activity (germinative cyst [GmC] morphometrics). As expected, the episodic CORT treatment had no effect on T plasma levels or spermatogenic activity. On the other hand, chronic CORT treatment reduced GmC morphometric traits, indicating suppression of reproduction, although T levels were not altered. In addition, animals from sham control and chronic CORT treatments with higher T levels presented higher WS, which indicates an immune-enhancing T effect.
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Affiliation(s)
- Débora M A Prado
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
| | - Fernando R Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
| | - Carla B Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo (USP), São Paulo, São Paulo State, Brazil
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Scaia MF, Volonteri MC, Czuchlej SC, Ceballos NR. Estradiol and reproduction in the South American toad Rhinella arenarum (Amphibian, Anura). Gen Comp Endocrinol 2019; 273:20-31. [PMID: 29555118 DOI: 10.1016/j.ygcen.2018.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/24/2018] [Accepted: 03/14/2018] [Indexed: 12/28/2022]
Abstract
Rhinella arenarum is a South American toad with wide geographic distribution. Testes of this toad produce high amount of androgens during the non reproductive season and shift steroid synthesis from androgens to 5α-pregnanedione during the breeding. In addition, plasma estradiol (E2) in males of this species shows seasonal variations but, since testes of R. arenarum do not express aromatase, the source of plasma E2 remained unknown for several years. However, the Bidder's organ (BO), a structure located at one pole of each testis, is proposed to be the main source of E2 in male's toads since it expresses several steroidogenic enzymes and is able to produce E2 from endogenous substrates throughout the year. In addition, there were significant correlations between plasma E2 and total activity of BO aromatase, and between plasma E2 and the amount of hormone produced by the BO in vitro. In the toad, apoptosis induced by in vitro treatment with E2 was mostly detected in spermatocytes during the breeding and in spermatids during the post-reproductive season, suggesting that this steroid has an important role in controlling spermatogenesis. However, in vitro treatment with E2 had no effect on proliferation. This evidence suggests that the mechanism of action of E2 on amphibian spermatogenesis is complex and more studies are necessary to fully understand the role of estrogens regulating the balance between cellular proliferation and apoptosis. In addition, in R. arenarum in vitro studies suggested that E2 has no effect on CypP450c17 protein levels or enzymatic activity, while it reduces 3β-hydroxysteroid dehydrogenase/isomerase (3β-HSD/I) activity during the post reproductive season. As well, E2 regulates FSHβ mRNA expression all over the year suggesting a down regulation process carried out by this steroid. The effect on LHβ mRNA is dual, since during the reproductive season estradiol increases the expression of LHβ mRNA while in the non-reproductive season it has no effect. In conclusion, the effect of E2 on gonadotropins and testicular function is complex, not clearly understood and probably varies depending on the species. The aim of the current article is to review evidence on reproductive endocrinology and on the role of estradiol regulating reproduction in amphibians, with emphasis on the South American species Rhinella arenarum.
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Affiliation(s)
- María Florencia Scaia
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA - CONICET), Buenos Aires, Argentina.
| | - María Clara Volonteri
- Instituto de Diversidad y Evolución Austral (IDEAus - CONICET), Puerto Madryn, Chubut, Argentina
| | - Silvia Cristina Czuchlej
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina.
| | - Nora Raquel Ceballos
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Biodiversidad y Biología Experimental, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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Joshi AM, Narayan EJ, Gramapurohit NP. Interrelationship among annual cycles of sex steroids, corticosterone and body condition in Nyctibatrachus humayuni. Gen Comp Endocrinol 2018; 260:151-160. [PMID: 29339182 DOI: 10.1016/j.ygcen.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/18/2017] [Accepted: 01/11/2018] [Indexed: 11/30/2022]
Abstract
Synergism between extrinsic and intrinsic factors is crucial for the seasonality of reproduction. Environmental factors such as photoperiod and temperature activate the hypothalamus-pituitary-gonadal axis leading to the secretion of steroid hormones that are crucial for reproduction. Sex steroids are not only essential for the maturation of gonads, but also for development of secondary sexual characters in males and reproductive behaviour of both the sexes. In the present study, we quantified the urinary testosterone (UTM) and corticosterone (UCM) metabolites in males and urinary estradiol metabolites (UEM) and UCM in females of Nyctibatrachus humayuni for two consecutive years to determine annual and seasonal variation in the levels of sex steroids, corticosterone and body condition index (BCI). The results show that sex steroids were highest during the breeding season and lowest during the non-breeding season in both the sexes. An increase in UTM and UEM was observed in males and females respectively during the breeding season. Testicular histology showed the presence of all stages of spermatogenesis throughout the year indicating that spermatogenesis is potentially continuous. Ovarian histology showed the presence of vitellogenic follicles only during the breeding season indicating that oogenesis is strictly seasonal. In males, UCM levels were highest during the breeding season, while in females their levels were highest just prior to the breeding season. In males, BCI was highest during the pre-breeding season, declined during the breeding season to increase again during the post-breeding season. In females, BCI was comparable throughout the year. In males, UTM levels were positively correlated with UCM levels but negatively correlated with BCI. Interestingly, UEM, UCM and BCI were not correlated in females. These results indicate that N. humayuni exhibits an associated pattern of reproduction. Quantification of urinary progesterone metabolites (UPM) during the breeding season showed UPM levels were higher in post-spawning females, suggesting the significance of progesterone in ovulation. Further, non-invasive enzyme immunoassay has been successfully standardized in N. humayuni for the quantification of urinary metabolites of steroid hormones.
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Affiliation(s)
- A M Joshi
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India
| | - E J Narayan
- School of Science and Health, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - N P Gramapurohit
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.
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Spermatogenic and Testosterone Cycles in a Desert-Adapted Amphibian Odontophrynus barrioi from the Monte Desert, Argentina. J HERPETOL 2018. [DOI: 10.1670/16-070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kisserli O, Moudilou E, Exbrayat JM. Sexual cycle and seasonal expression of testosterone (T) in the testes of Sclerophrys mauritanica (Schlegel, 1841). AFR J HERPETOL 2017. [DOI: 10.1080/21564574.2017.1369170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Affiliation(s)
- Omar Kisserli
- Laboratoire de Biotechnologie, Environnement et Santé. Université Mohamed Seddik Benyahia-Jijel. BP. 98. Ouled Aïssa, Jijel (18000) –Algérie
| | - Elara Moudilou
- Université de Lyon, UMRS 449, Biologie Générale - Reproduction et Développement Comparé, Université Catholique de Lyon - EPHE/PSL, 10 place des archives, F-69288 Lyon Cedex 02, France
| | - Jean-Marie Exbrayat
- Université de Lyon, UMRS 449, Biologie Générale - Reproduction et Développement Comparé, Université Catholique de Lyon - EPHE/PSL, 10 place des archives, F-69288 Lyon Cedex 02, France
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Bradshaw SD. A state of non-specific tension in living matter? Stress in Australian animals. Gen Comp Endocrinol 2017; 244:118-129. [PMID: 26449159 DOI: 10.1016/j.ygcen.2015.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/27/2015] [Accepted: 10/03/2015] [Indexed: 10/22/2022]
Abstract
Evidence of stress responses in Australian animals is reviewed through a series of case studies involving desert frogs and lizards, small carnivorous marsupials, desert wallabies, a dwarf kangaroo species, the quokka wallaby and a small nectarivorous bird. An operational definition of stress as "the physiological resultant of demands that exceed an animal's homeostatic capacities" is used to identify instances of stress responses in the field, and to gauge their intensity. Clear evidence of stress responses is found in small dasyurid marsupial carnivores, and desert agamid lizards, both of which are semelparous. Other instances of seasonal stress responses include the Rottnest Island quokka, the Barrow Island euro kangaroo and a small nectarivorous bird, the Silvereye. The review also highlights the high level of physiological adaptation of some desert wallabies, such as the Spectacled hare wallaby, which is able to maintain physiological homeostasis in the field when challenged by conditions of extreme drought. The importance of thermal and hygric refugia for the long-term survival or rock wallabies, which apparently lack any hormonal control of renal function, is also highlighted.
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Affiliation(s)
- S Don Bradshaw
- School of Animal Biology, The University of Western Australia, Perth, WA 6009, Australia.
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Madelaire CB, Gomes FR. Breeding under unpredictable conditions: Annual variation in gonadal maturation, energetic reserves and plasma levels of androgens and corticosterone in anurans from the Brazilian semi-arid. Gen Comp Endocrinol 2016; 228:9-16. [PMID: 26808964 DOI: 10.1016/j.ygcen.2016.01.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 01/13/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Anurans living in arid and semi-arid habitats are subjected to unpredictable rain patterns. Consequently, they should be prepared to reproduce at the onset of rain events. We investigated the covariation between calling behavior, testicular maturation, abdominal fat body index (FBI), plasma levels of androgens (T-DHT) and corticosterone (CORT) of males from three species of anurans in the Brazilian semi-arid during the reproductive period and drought. One of these species aestivates during the drought, while the other two species remain foraging. Although the three species display different behavioral strategies during the dry period, they present the same general reproductive patterns. T-DHT levels on the plasma and germinative cyst diameters were higher during the reproductive and breeding period compared to the drought. Additionally, the germinative cysts had all cell stages including sperm bundles during the dry season, however, it was only during the breeding event that free spermatozoa were found in the cyst lumen. These results suggest that these species present the reproductive pattern typical of desert anurans, consisting of opportunistic breeders that reproduce when triggered by a rain stimulus. Rhinella jimi and Pleurodema diplolister had higher CORT when males were calling. Moreover, Rhinella granulosa and P. diplolister showed lower FBI during breeding event, when males were calling. The high levels of CORT and lower FBI during reproductive period are associated, indicating that CORT modulates the recruitment of energy stores to prepare and maintain reproduction, particularly the expensive calling effort.
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Affiliation(s)
- Carla Bonetti Madelaire
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav. 14, n° 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
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Alon G, Shore LS, Steinberger Y. Correlation between levels of sex hormones (progesterone, testosterone, and estrogen) and ecophysiological-behavior stages in two species of desert snails (Sphincterochila zonata and Sphincterochila prophetarum) in the Northern Negev Desert. Gen Comp Endocrinol 2007; 151:122-7. [PMID: 17289044 DOI: 10.1016/j.ygcen.2006.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Revised: 12/11/2006] [Accepted: 12/26/2006] [Indexed: 11/24/2022]
Abstract
The steroidal hormonal profiles of two sympatric species of desert snails, Sphincterochila zonata and Sphincterochila prophetarium were determined at three ecophysiological-behavior stages, i.e., aestivation, cryptobiosis, and active-feeding phases. Live snails were collected in their natural habitat every month for 13 months, the corpi removed and extracted with organic solvents and the progesterone, testosterone, and estrogen concentrations determined by radioimmunoassay. In both these hermaphroditic species during aestivation, a peak of testosterone followed by a peak of estrogen was observed. During the brief active intervals, minor peaks of estrogen were also observed but these were much lower than seen during aestivation. Although the two species have different microhabitats during aestivation, there was little difference in the hormonal profile, although S. prophetarum had about two fold higher progesterone concentration than S. zonata.
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Affiliation(s)
- G Alon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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