BACKGROUND: This study has addressed concerns about possible effects of feeding @entity1 @entity1 soy formula milk (SFM). METHODS: This is a feeding study in marmosets, using a mainly co-twin design. From 4-5 until 35-45 days of age, co-twin males were fed by hand with either standard ( @entity291 ) formula milk ( @entity4574 = controls) or with SFM for approximately 8 h each day (2 h at weekends) and intake related to bodyweight. Blood samples were collected at 18-20 and at 35-45 days of age in 13 sets of co-twins plus two non-twin males per group and, at the later age, seven sets of co-twins were killed and the testes and pituitary gland fixed for cell counts. RESULTS: @entity1017 were similar in both feeding groups. @entity4574 -fed males had mean @entity251 levels of 2.8-3.1 ng/ml, typical of the "neonatal @entity251 rise", whereas SFM-fed males exhibited consistently lower mean levels (1.2-2.6 ng/ml); paired comparison in @entity4574 -and SFM-fed co-twins at day 35-45 revealed 53-70% lower levels in 11 of 13 co-twins fed with SFM (P = 0.004). Further evidence for suppression of @entity251 levels in SFM-fed males came from comparison of the frequency of low @entity251 levels (<0.5 ng/ml). In historical controls aged 35-45 days, two out of 22 values were <0.5 ng/ml, a similar frequency as found in control @entity4574 -fed males (one out of 15 values <0.5 ng/ml). In contrast, 12 out of 15 values for SFM-fed males were <0.5 ng/ml (P < 0.001). There was no consistent relationship between SFM intake/g and @entity251 levels. Paradoxically, the mean number of Leydig cells per testis was increased by 74% (P < 0.001) in co-twins fed SFM, when compared with their @entity4574 -fed brothers, whereas no significant changes were found in numbers of Sertoli and germ cells. Because of the lack of gonadotrophin assays, the number of immunopositive @entity6753 and @entity6752 cells in the pituitary gland, and their ratio, were determined but no consistent difference was found between @entity4574 - and SFM-fed twins. CONCLUSIONS: Based on the average @entity3093 content of the SFM brand used, intake of @entity6400 was estimated at 1.6-3.5 mg/kg/day in the SFM-fed marmosets which is 40-87% of that reported in 4 month @entity1 @entity1 fed on a 100% SFM diet. It is therefore considered likely that similar, or larger, effects to those shown here in marmosets may occur in @entity1 male @entity1 fed with SFM. Whether the changes described result in longer-term effects is under investigation.

@entity1 feeding with soy formula milk: effects on the testis and on blood XXXX levels in marmoset monkeys during the period of neonatal testicular activity.

@entity1 :: ('9606', 'Species') :: ['human', 'infants'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone'] @entity4574 :: ('MESH:D014897', 'Disease') :: ['SMA'] @entity6400 :: ('MESH:D007529', 'Chemical') :: ['isoflavones'] @entity3093 :: ('CHEBI:18220', 'Chemical') :: ['isoflavone'] @entity6753 :: ('3972', 'Gene') :: ['LHbeta'] @entity1017 :: ('MESH:D015430', 'Disease') :: ['Weight gain and formula intake'] @entity291 :: ('9913', 'Species') :: ['cow'] @entity6752 :: ('2488', 'Gene') :: ['FSHbeta']
@entity251 :: (MESH:D013739,Chemical) :: ['testosterone']
