Cord blood insulin-like peptide 3 (INSL3) but not testosterone is reduced in idiopathic cryptorchidism.
BACKGROUND
Cryptorchidism, the most frequent congenital malformation in full-term male newborns, increases the risk of hypofertility and testicular cancer. Most cases remain idiopathic but epidemiological and experimental studies have suggested a role of both genetic and environmental factors. Physiological testicular descent is regulated by two major Leydig hormones: insulin-like peptide 3 (INSL3) and testosterone.


OBJECTIVE
To study the endocrine context at birth as a reflection of late pregnancy in isolated idiopathic cryptorchidism and to analyse the possible disruptions of INSL3 and/or testosterone.


METHODS
From a prospective case-control study at Nice University Hospital, we assessed 180 boys born after 34 weeks gestation: 52 cryptorchid (48 unilateral, 4 bilateral; 26 transient, 26 persistent), and 128 controls matched for term, weight and time of birth. INSL3 and testosterone were measured in cord blood and compared in both groups as were other components of the pituitary-gonadic axis: LH, HCG, FSH, AMH and SHBG.


RESULTS
INSL3 was decreased in cryptorchid boys (P = 0·031), especially transient cryptorchid (P = 0·029), while testosterone was unchanged as were the other hormones measured. INSL3 was significantly decreased (P = 0·018) in the group of 20 with nonpalpable testes compared with the group of 21 with palpable testes (15 suprascrotal, five inguinal, one high scrotal) according to Scorer classification. In the whole population, INSL3 correlated positively with LH and negatively with AMH, but with no other measured hormones.


CONCLUSIONS
INSL3 but not testosterone is decreased at birth in idiopathic cryptorchidism, especially in transient forms. This hormonal decrease may contribute to the impaired testicular descent along with genetic and anatomical factors. Whether foetal environment (nutritional and/or toxicological) interferes with INSL3 secretion in humans remains to be confirmed.
Department of Endocrinology, Diabetology and Reproductive Medicine, CHU Nice, Nice, France; Institut National de la Recherche Médicale, UMR U1065, Université Nice-Sophia Antipolis, Nice, France.
Patrick
P
Fénichel
Najiba
N
Lahlou
Patrick
P
Coquillard
Patricia
P
Panaïa-Ferrari
Kathy
K
Wagner-Mahler
Françoise
F
Brucker-Davis
D001724:Birth Weight; D016022:Case-Control Studies; D003456:Cryptorchidism / Q000097:blood*; D015536:Down-Regulation; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood*; D008297:Male; D011247:Pregnancy; D011506:Proteins; D013739:Testosterone / Q000097:blood*
D007328:Insulin; C084797:Leydig insulin-like protein; D011506:Proteins; D013739:Testosterone