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Testicular cycles in three species of Korean frogs: Rana nigromaculata, Rana rugosa, and Rana dybowskii.

Abstract：

:Seasonal changes in testicular structure and function in three species of Korean frogs (Rana nigromaculata, R. rugosa, and R. dybowskii) having different breeding seasons and habitats were examined throughout the year. R. nigromaculata live in rice fields and breed in early May. Their gonadosomatic index (GSI) and testis weight decreased slightly from May until July, but increased markedly from August to high levels through December. The diameter (cross-sectional area) of seminiferous tubules changed little from January until August, increased sharply from September through October, and decreased thereafter. In seminiferous tubules, the number of primary spermatogonia (I SPG) was low from January-March, increased from April to maximum levels by May-June, and decreased subsequently. The number of spermatids (SPT) was highest from November to March, decreased to nondetectable levels in May, and increased markedly from September to November. Spermiation was most active during March and April. R. rugosa, which live in streams and breed during May-June, exhibited no changes in GSI, testis weight, or seminiferous tubule size throughout the year. The number of I SPG was high during May-August and that of secondary spermatogonia (II SPG) was highest in August. The number of SPT increased to high levels in November-December. Active spermiation occurred from January to April in this frog. In R. dybowskii, which live in the mountains and breed from late February to early March, the number of I SPG gradually increased from April through August; however, essentially no other spermatogenic cells were observed from January to July. A marked increase in early spermatogenic cells appeared during August-September and was followed by an increase in SPT from November to December. From December to March the number of spermatozoa increased and spermiation occurred. In general, testicular testosterone levels were high in the winter and low in summer in all three species, and positively correlated with the number of interstitial cells and the size of their nucleus.

journal_name

Gen Comp Endocrinol

journal_title

General and comparative endocrinology

authors

Ko SK,Kang HM,Im WB,Kwon HB

doi

10.1006/gcen.1998.7118

subject

Has Abstract

pub_date

1998-09-01 00:00:00

pages

347-58

issue

eissn

0016-6480

issn

1095-6840

pii

S0016648098971180

journal_volume

111

pub_type

杂志文章

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Testicular cycles in three species of Korean frogs: Rana nigromaculata, Rana rugosa, and Rana dybowskii.