Ultrastructural evidence of indirect and direct autonomic innervation of human Leydig cells: comparison of neonatal, childhood and pubertal ages

Abstract

Recent physiological studies have indicated an autonomic influence on the secretion of testosterone from Leydig cells in humans and laboratory animals. Furthermore, a few studies have shown enhanced autonomic control of Leydig cell function in immature, relative to mature, laboratory animals. In the current ultrastructural study of the human testicular interstitium the morphology of autonomic components is described from neonatal, childhood and pubertal ages. Autonomic nerve fibers and varicosities with neurotransmitter vesicles are described in proximity to Leydig cells. The observed autonomic terminals are classified by vesicle morphology into three general types: (1) Type I with predominantly small agranular vesicles (30-60 nm) and occasional larger granular vesicles (100 nm). This type is morphologically consistent with being cholinergic. (2) Type II with predominantly small granular vesicles (30-60 nm), as well as sporadic large granular vesicles. These are morphologically consistent with adrenergic terminals. (3) Type III which exhibit numerous large granular vesicles of mixed size. Evidence of autonomic terminals is encountered most frequently in childhood biopsies, age 3 to 10 years. The neonatal specimen (4 months) is noteworthy in that many of the Schwann cells appear immature and no adrenergic terminals are observed. In contrast, terminals morphologically consistent with being adrenergic are common in the childhood series of biopsies. Although the vast majority of the autonomic terminals are associated with Leydig cells indirectly as "boutons en passant", separated by approximately 150 nm to more than a micron, evidence of direct contact (20 nm) of autonomic terminals with Leydig cells is presented.(ABSTRACT TRUNCATED AT 250 WORDS)

Peptidergic not monoaminergic fibers profusely innervate the young adult human testis

“…Using electron microscopy, Prince (1984Prince ( , 1992Prince ( , 1996 examined autonomic nerves in human testis from the neonatal period, childhood and puberty, and revealed an age-dependent change. He found that newborn gonads exhibited no adrenergic innervation.…”

Mitochondrial structure in steroid‐producing cells: Three‐dimensional reconstruction of human Leydig cell mitochondria by electron microscopic tomography

“…Cases negative for leukemic cells have been used in a number of studies regarding human Leydig cell development and cell biology (Prince, 1984(Prince, , 1992(Prince, , 1999(Prince, , 2002. The present tomography study utilizes a postpubertal specimen to reconstruct mitochondria of the adult maturation phase.…”

Novel identification of peripheral dopaminergic D2 receptor in male germ cells

“…Catecholamines are likely to play a special part in this ''neuroendocrinotrophic stimulatory complex'' [Gnessi et al, 1997]. The catecholamines found in the gonads may be derived from sympathetic innervation or from the adrenal gland via the blood stream [Campos et al, 1990;Prince, 1992Prince, , 1996Rauchenwald et al, 1995;Stjernquist, 1996]. In human and non-human primate species, neuron-like cells identified as novel member of the interstitial cell compartment expressing neuron-specific intermediate filament (NF-200) and tyrosine hydroxylase (TH) could be another potential source of catecholamines present in the ovary and testis [Dees et al, 1995;Mayerhofer et al, 1996, 1999b, Frungieri et al, 2000.…”