Table 1

Differences between the sex groups and the cross-correlations between the variables

M

(g)

BM

(g)

BM/M

HC

(mm³)

Trp

(ng/mL)

5-HT

(ng/mL)

5-HT/

Trp

Gut

(mm)

Sex

F < M

F < M

F > M

F < M

F < M

F > M

F > M*

F > M

.185

.273

.325

.286

.584

.245

.040

.861

63

63

63

17

58

58

58

33

M

.768**

-.825**

.662**

-.089

-.594**

-.304*

.688**

< 10^-6

< 10^-6

.004

.507

10^-6

.020

10^-5

63

63

17

58

58

58

33

BM

-.165

.619**

.056

-.433**

-.262*

.400*

.196

.008

.676

.001

.047

.021

63

17

58

58

58

33

BM/M

-.571*

.229

.465**

.315*

-.745**

.017

.084

2·10^-4

.016

10^-6

17

58

58

58

33

HC

-.638**

-.505*

-.124

.427

.008

.046

.649

.146

16

16

16

13

Trp

.116

-.430**

-.293

.387

.001

.110

58

58

31

5-HT

.818**

-.264

< 10^-6

.152

58

31

5-HT/Trp

-.004

.983

31

N

63

63

63

17

58

58

58

33

Mean

6.511

.387

.061

8.127

16424

2069

.128

221.30

STD

.954

.028

.008

1.054

2439

536

.037

11.25

Abbreviations: M, body mass; BM, brain mass; HC, volume of the hippocampal complex; Trp, blood tryptophan concentration; 5-HT, blood 5-HT concentration; Gut, length of the relaxed gut; N, total number of cases; STD, standard deviation. The two sex groups were compared using the exact Mann-Whitney test if the variable was BM/M or 5-HT/Trp; otherwise, Student's independent t-test was used. Spearman's correlation was used if either of the two non-dichotomous variables was BM/M or 5-HT/Trp; otherwise, Pearson's correlation was used. In the sex row, the "greater than" ("less than") sign indicates that the mean of the female group was greater (less) than the mean of the male group. In all other cells, the first number is the value of the correlation coefficient. In all cells, the second (bold) number is the significance of the corresponding test. In all cells, the third number is the total number of cases used in the test. The residuals of the linear regression with sex as the predictor variable and M or 5-HT as the dependent variable were not normally distributed (p = 6·10^-5 and 8·10^-6, respectively). Therefore, the differences between the mean M and 5-HT values in the two sex groups were retested with the exact Mann-Whitney test, which confirmed they were not significant (p = 0.124 and 0.168, respectively).

Albay et al. BMC Physiology 2009 9:4   doi:10.1186/1472-6793-9-4