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The early differentiation of the testis and interstitial cells in the fetal pig, and its duplication in organ culture

1973; Wiley; Volume: 138; Issue: 2 Linguagem: Inglês

10.1002/aja.1001380209

1553-0795

Young Soo Moon, Margaret H. Hardy,

Xenotransplantation and immune response

Abstract The unusual histogenesis of the fetal pig testis was examined as part of a study of its role in reproductive biology. Three types of interstitial cells were defined and their numbers estimated per unit area of testicular tissue in 6 μ‐serial sections. Statistical analysis of the percentage frequency of each cell type showed that the mature Leydig cells (C‐type) reached a peak at about 4.5 cm crown‐rump length (CRL) fetus and then fell to a low level, rising again sharply from 20 cm CRL until near birth. It was postulated that the first mature Leydig (C‐type) cells arose from mesenchymal (A‐type) cells which differentiated first into immature Leydig (B‐type) cells, and the process was repeated in the last part of fetal life. Mixtures of cock plasma, chicken embryo extract and balanced salt solution allowed maintenance and differentiation of whole fetal testes or testicular slices as organ cultures in Maximow slide assemblies for 6 to 14 days. Medium 199 with 10% bovine serum allowed maintenance and differentiation in some explants for at least six days. Indifferent gonads developed into recognizable testes or ovaries. Testes from 2.5, 3.0, and 3.5 cm CRL fetuses differentiated at a fairly normal rate, and some of their interstitial cells underwent the transformation postulated from the in vivo study. It was concluded that organ cultures from indifferent gonads and early testes provided living, functioning systems which could be used to test for androgenic activity with biological indicators.