INDUCTION OF OVARIAN FOLLICULAR DEVELOPMENT IN THE SUBADULT FROG RANA-TIGRINA USING LUTEINIZING-HORMONE-RELEASING HORMONE-ACETATE

In the subadult Rana tigrina administration of 2 mu g luteinizing horm one releasing hormone-acetate/frog six days a week for 4 weeks in Apri l resulted in the formation of medium (in all 8 frogs) and large sized (in 4 out of 8 frogs) yolky oocytes and, concomitant increases in the oviductal mass. The ovarian and oviductal masses showed a 10-fold inc rease over the control frogs. In untreated frogs the ovaries were tran sparent and contained first growth phase oocytes only. The oviducts we re also infantile. The pituitary sections were stained using antisera raised in rabbit against the beta-subunit of human luteinizing hormone and human follicle stimulating hormone. Immunoreactivity, staining in tensity, cytoplasmic granulation and, cell, nuclear and cytoplasmic ar eas of gonadotrophs (B-2 cells) increased significantly in luteinizing hormone releasing hormone treated frogs. The above findings suggest t hat pituitary-ovarian axis in the subadult Rana tigrina is responsive to luteinizing hormone releasing hormone and that long-term treatment with the hormone induces cytomorphological changes in the gonadotrophs which result in the conversion of inactive cells into secretory cells . This is accompanied by precocious vitellogenic growth of oocytes in the subadult frogs.