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Abstract

The localization of messenger ribonucleic acids for somatostatin receptors 1, 2, and 3 in rat testis (PDF) (HTML) 
Zhu,Li-Ji; Krempels,Krisztina; Bardin,C.Wayne; O'Carroll,Anne-Marie; Mezey,Eva
Endocrinology 139(1): 350-357
Publication date: 1998

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Somatostatin (SRIF) exerts multiple inhibitory actions throughoutthe body by binding to specific SRIF receptors (sst). In recentyears, five subtypes of SRIF receptors (sst1-5) have beencloned. In this study, S-labeled complementary RNA probeswere used for in situ hybridization to localize the sst1-5messenger RNAs (mRNAs) in the rat testis and examine the changesin their distribution during the cycle of the seminiferous epithelium.We found that sst 1-3 mRNAs were visualized in rat testesand were mainly localized within the seminiferous tubules. Thesignal for sst3 mRNA was also found in interstitial cells. sst4and 5 mRNAs were not detected in rat testes with the methodused in this study. In Sertoli cells, the most intense labelingfor sst1 and 3 mRNAs was in stages IV-VII of the cycleof the seminiferous epithelium, which coincided with the lowest labelingintensity for sst2. In germ cells, sst1-3 mRNAs showed similarpatterns of distribution. In these cells, sst1-3 mRNAwas not observed at the early steps of spermatogenesis. Positivesignals for sst1-3 mRNAs were first apparent in the pachytenespermatocytes at stage VII and last until stage XII and in thediplotene spermatocyte at stage XIII. Positive signals for sst1-3were also detected in round spermatids at stages I-VIII.Labeling of spermatids dramatically decreased at stage IX, whenthese cells began their elongating changes. The presence ofthree sst in testis suggests that SRIF may play an essentialrole in testicular function.

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