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Titolo:
TESTICULAR CYCLES IN 3 SPECIES OF KOREAN FROGS - RANA-NIGROMACULATA, RANA-RUGOSA, AND RANA-DYBOWSKII
Autore:
KO SK; KANG HM; IM WB; KWON HB;
Indirizzi:
CHONNAM NATL UNIV,HORMONE RES CTR KWANGJU 500757 SOUTH KOREA CHONNAM NATL UNIV,HORMONE RES CTR KWANGJU 500757 SOUTH KOREA CHONNAM NATL UNIV,DEPT BIOL KWANGJU 500757 SOUTH KOREA HONAM UNIV,DEPT BIOL KWANGJU 502791 SOUTH KOREA CHUNGBUK NATL UNIV,DEPT GENET ENGN CHONJU 360764 SOUTH KOREA
Titolo Testata:
General and comparative endocrinology (Print)
fascicolo: 3, volume: 111, anno: 1998,
pagine: 347 - 358
SICI:
0016-6480(1998)111:3<347:TCI3SO>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
PLASMA GONADOTROPINS; SEX STEROIDS; PITUITARY; BULLFROG; CATESBEIANA; ESCULENTA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
22
Recensione:
Indirizzi per estratti:
Citazione:
S.K. Ko et al., "TESTICULAR CYCLES IN 3 SPECIES OF KOREAN FROGS - RANA-NIGROMACULATA, RANA-RUGOSA, AND RANA-DYBOWSKII", General and comparative endocrinology (Print), 111(3), 1998, pp. 347-358

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 levelsthrough December. The diameter (cross-sectional area) of seminiferoustubules 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.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 21:54:52